Two weather highlights in July were the exceptionally cool weather in parts of the Midwest and East and the extreme heat in the West, so let’s take a quick look at temperature anomalies (departures from normal) for July 2009:
Temperature anomalies for North America in July 2009 (Image courtesy of Earth System Research Laboratory)
For those unfamiliar with looking at weather maps such as this, the scale indicates the number of degrees above average (green to red) or below average (blue to purple) areas on the map were during July 2009.
The areas below normal are impressive, with many daily record low temperatures being established and a few locations having their coolest July on record, including Flint and Saginaw, Michigan. This will undoubtedly feed the misnomer of this being The Year Without a Summer.
The hot areas were impressive as well, with the hottest July on record in Phoenix, Arizona and the second hottest July on record in Portland, Oregon. This will undoubtedly feed the belief that any hot weather is proof of global warming.
What Does it Mean?
It means that the weather pattern was dramatic and persistent during the month of July, which is an indication of the natural variation of the weather. The so-called normal weather is merely an average of all types of weather, including extreme seasons like this one.
These types of weather patterns are nothing new, and we can no more draw conclusions about whether global warming is–or is not–occuring from one month of weather records any more than a person can draw conclusions about life-long finances based on day of records. If we base all of our accounts about finances based on the day that the pay check arrived, we might unfairly conclude that finances are great; if we base it on two days later when no money arrives and all of the bills were subtracted, we might unfairly conclude that we’re financially hopeless.
–Paul Yeager
